Dye image formation in silver halide light-sensitive materials is effected by exposure to light and color development processing in which a developing agent, e.g., aromatic primary amines, oxidized with silver halide is allowed to react with a dye forming coupler. In this image formation system, color reproduction is generally achieved by a subtractive color process, in which blue, green, and red colors are reproduced by forming the complementary colors, i.e., yellow, magenta, and cyan dyes, respectively.
Cyan dye forming couplers (also typically referred to more simply as "cyan couplers") widely employed include phenol couplers and naphthol couplers. However, dye images obtained from the conventionally employed phenol and naphthol couplers have some problems remaining unsolved in terms of preservability. For example, dye images obtained from 2-acylaminophenol cyan couplers as described in U.S. Pat. Nos. 2,367,531, 2,369,929, 2,423,730, 2,801,171, etc., are generally inferior in fastness to heat; those obtained from 2,5-diacylaminophenol cyan couplers as described in U.S. Pat. Nos. 2,772,162 and 2,895,826 are generally inferior in fastness to light; and those obtained from 1-hydroxy-2-naphthamide cyan couplers are generally insufficient in fastness to both light and heat, particularly wet heat.
5-Hydroxy-6-acylaminocarbostyril cyan couplers described in U.S. Pat. Nos. 4,327,173 and 4,564,586, and 4-hydroxy-5-acylamino-oxyindole couplers, 4-hydroxy-5-acylamino-2,3-dihydro-1,3-benzimidazol-2-one couplers, etc., described in U.S. Pat. No. 4,430,423 are excellent in light and heat fastness, but are disadvantageous in that the white background in unexposed areas undergoes yellow staining.